"Alexandr Alexandr" <a223253100 at yahoo.com> wrote in message
news:edqr42$t4p$1 at smc.vnet.net...
>
> How would I solve the following problem with
> Mathematica?
> x'(t) + x(t-1) = 0.
Step 1.
Go to the help Index
Step 2
look up RSolve